It is known in the art that removal of harmful contaminants from water is essential to the health, safety and welfare of individuals and the public at large. It is of particular importance to ensure the adequacy of potable water supplies as these supplies become increasingly burdened and threatened by pollutants and other contaminants. In particular, there is substantial concern regarding the long term effects on humans of particularly volatile compounds such as hydrogen sulfide, methane, VOC's (volatile organic compounds), radon, etc., all of which can be found infiltrating and contaminating existing water supplies.
The typical procedure for removing volatile gaseous components from a contaminated water supply is by aeration of the water. Aeration is the process of contacting water with a supply of air and is currently the most preferred method of removing the above mentioned volatile compounds prior to domestic use of water. In conventional aeration processes, generally as much air as possible is introduced into a liquid in order to provide an increased water surface area for absorption of gases, volatile or otherwise, dissolved within the liquid to be aerated.
According to one known system, a supply of potentially contaminated water is conveyed across a large tray or a series of trays as a thin, laminar sheet to increase the exposed surface area of the water to as much air as possible in order to create diffusion of as much of the saturated, contaminating volatile gases as possible. The saturated, contaminating volatile gases removed by this prior art system are then vented to the outside atmosphere.
With reference to FIG. 1, a brief description concerning a second known prior art system will now be discussed. This system has a water inlet which supplies potentially contaminated water from a well or any desired water source, and stores the water in a contaminated water storage tank ST. A solenoid control valve controls the flow rate of contaminated water to the aerating tank AT with the valve control being controlled by conventional sensors located within the aerating tank AT. The water thus flows from the contaminated water storage tank ST into the aerating tank AT and fills a number of sequentially arranged aeration chambers AC formed within the aerating tank AT. Each one of the aeration chambers AC, in the aerating tank AT, contains a segment of a bubble diffuser BD from which forced air emanates to cleanse the water situated in each one of the aeration chambers AC. The air is forced through the bubble diffuser BD and into the separate aeration chambers AC by a conventional blower and the air, after passing through the water and scrubbing contaminates therefrom, rises to the surface of the water and exits the aerating chamber AC via an exhaust outlet EO and is conveyed to the outside ambient environment.
The cleansed or scrubbed water then exits the aeration tank AT and enters a water output pipe. Because the water has become depressurized while being treated within the aeration chamber AC, a pump RP is necessary to re-pressurize the treated water to a desired water pressure, e.g. the typical household water pressure is generally between 30-60 psi. The re-pressurized water is conveyed either into a treated water storage tank ST or directly to the end user facility.
One major drawback with both of the above known prior art volatile contamination removal systems is that they generally operate solely by a single aeration method of the supplied water.
These aeration systems exemplify the gaseous diffusion process whereby gases tend to flow from a medium including a high concentration of a gas to another medium having a lower concentration of the gas. Between the two mediums, the diffusing gas must pass through a boundary layer and, in general, the greater the surface area of the boundary layer the more gas which is induced to diffuse across the boundary layer. In any gaseous diffusion process, the extent to which any saturated gas will diffuse across a unit area of fluid boundary layer is dependant upon a fixed coefficient derived from the nature and characteristics of the diffusing media, the boundary layer between them and the saturated gas. Thus, the greater the unit area of boundary layer between the fluids, the greater the amount of gas which can diffuse across the boundary layer. The practical significance of this is that the more air to water boundary layer contact which can be accomplished, the greater the rate of diffusion of harmful saturated volatile compounds and other particles from the water and into the diffusing air.
To the extent that air bubble diffusers are adequate in removing many contaminants from water, there is a great need to increase the efficiency and efficacy of such existing systems to produce healthy potable water. For this reason, there is a great need to provide a greater air to water boundary layer contact and increase the rate of diffusion to remove a higher percentage of contaminants from the water within a shorter time period.